Benzodiazepines are among the most highly prescribed classes of drugs due to their anxiolytic actions via high or higher than that of GABA(A) receptors. PBZD binding sites are also present in many peripheral tissues. the function of these binding sites and the pharmacological actions of benzodiazepines mediated at PBZD binding sites are also present in many peripheral tissues. The function of these binding sites and the pharmacological actions of benzodiazepines mediated at PBZD binding sites and the complexes with which they are associated. A protein entitled PKBS, purified from the PBZD binding structure, will be cloned and sequenced. The full-length PKBS-cDNA probe will be manipulated to examine functional expression of PBZD binding sites in eukaryotic host cells. The tools and methods to determine PBZD receptor function will then be possible with recombinant DNA technology. In situ hybridization will be used to localize and identify specific cells expressing PKBS in the brain. Identification of potentially homologous proteins in brain and in lower classes of vertebrates will be attempted by Northern analysis. The native complexes to which PKBS is associated will be purified and all molecular components of these complexes will be characterized biochemically and immunochemically. The interaction of diazepam-binding inhibitor, a putative endogenous brain polypeptide ligand for PBZD and central benzodiazepine binding sites, will be studied by cross-linking methods to determine the recognition site for this molecule on PBZD binding site for this molecule on PBZD binding site complexes in relation to their subunit composition. The long-term objectives of this work are to elucidate the function of PBZD receptors and understand the consequences that the binding of benzodiazepines may have on this physiological process.